Apparatus for operating cassette of photosensitive element in electrophotographic copier

ABSTRACT

An apparatus comprising coupling means engageable with a stock shaft and a take-up shaft of a photosensitive element cassette and selectively engageable with a stock roller and a take-up roller accommodating the shafts respectively to couple the rollers together, a tension mechanism engageable with and disengageable from the stock roller and the take-up roller to tension a photosensitive element extending between the rollers when in engagement with the rollers, a drive mechanism for driving the take-up shaft and the take-up roller in sequence when in engagement with the coupling means, and operation mechanism for shifting the tension mechanism and the coupling means. Freeing the photosensitive element from the tension, winding-up of the element into the take-up roller, pulling-out of the element from the stock roller and tensioning of the element are conducted full-automatically.

United States Patent [1 1 Tanaka et al.

[451 Jan. 21, 1975 {22] Filed: Mar. 27, 1973 [2!] Appl. No.: 345,381

[30] Foreign Application Priority Data Apr. 13, 1972 Japan 47-37535 [52] U.S. Cl. 242/673 R, 355/l6 [Sl] Int. Cl 1365!! 17/02, 003g 15/00 [58] Field of Search 242/67.4, 67.3 R, 75;

[56] References Cited UNITED STATES PATENTS 8/1950 Thompson 242/674 12/1965 Hunstiger 355/l6 X ll/l97l Swanke 355/17 Limberger 355/16 X Van Meijel 242/674 [57] ABSTRACT An apparatus comprising coupling means engageable with a stock shaft and a take-up shaft of a photosensitive element cassette and selectively engageable with a stock roller and a take-up roller accommodating the shafts respectively to couple the rollers together, a tension mechanism engageable with and disengageable from the stock roller and the take-up roller to tension a photosensitive element extending between the rollers when in engagement with the rollers, a drive mechanism for driving the take-up shaft and the take up roller in sequence when in engagement with the coupling means, and operation mechanism for shifting the tension mechanism and the coupling means. Freeing the photosensitive element from the tension, winding-up of the element into the take-up roller, pulling out of the element from the stock roller and tensioning of the element are conducted full-automatically.

10 Claims, 11 Drawing Figures PATENTED JANZ] 5 SHEET 30F 6 APPARATUS FOR OPERATING CASSETTE OF PHOTOSENSITIVE ELEMENT IN ELECTROPIIOTOGRAPI-IIC COPIER BACKGROUND OF THE INVENTION The present invention relates to an apparatus for operating a cassette of photosensitive element in electrophotographic copiers of the image transfer type, more particularly to an apparatus for operating a photosensitive element cassette to be loaded in an electrophotographic copier of the electrostatic latent image transfer type in which an electrostatic latent image formed on the photosensitive element is transferred to copy paper or of the powder image transfer type in which the electrostatic latent image on the photosensitive element is visualized with a powdered toner and the visualized image is then transferred to copy paper.

With this type of electrophotographic copiers, a sheet of photosensitive element in the form of a belt supported in a cassette is driven reciprocally to be subjected to charging, exposure and image transfer operation during the forward travel and to return after the completion of image transfer. The photosensitive element is housed in the cassette in such manner that the fresh portion of the photosensitive element is accommodated in a stock roller supported in the cassette and the fatigued portion due to repeated use is wound up into a take-up roller similarly supported in the cassette.

In addition to a drive mechanism for travelling the photosensitive element back and forth for the copy operation, electrophotographic copiers of the image transfer type require a mechanism for winding up the fatigued photosensitive portion into the take-up roller and pulling out a required length of fresh photosensitive portion, a mechanism for imparting a suitable tension to the photosensitive element during operation to keep the same planar at the exposure station, and a mechanism for holding the element in intimate contact with copy paper at the transfer station so as to travel the element at the same speed as the copy paper and to effect the image transfer. These mechanisms must be incorporated into the copier and so constructed that when the cassette is loaded in the copier they will be coupled to the stock roller and the take-up roller for a trouble-free operation.

SUMMARY OF THE INVENTION An object of this invention is to provide an apparatus for operating a cassette of photosensitive element to be loaded in electrophotographic copiers of the image transfer type by which a fatigued portion of the sheet of photosensitive element can be wound up and a specifled length of fresh photosensitive portion can be pulled out from a stock roller full-automatically.

Another object of this invention is to provide an apparatus of the type described for imparting a suitable tension to the operative portion of the photosensitive element to keep the same planar at the exposure station and to assure intimate contact between the element and copy paper at the transfer station.

Another object of this invention is to provide an apparatus as described with a compact construction so as to be accommodated in a small space.

Still another object of this invention is to provide an apparatus of the type described which operates reliably and which can be controlled automatically with ease.

LII

The cassette of photosensitive element comprises a stock roller rotatably supporting therein a stock shaft for stocking a sheet of photosensitive element in the form of a wound-up belt and formed with a slit for pulling out the photosensitive element wound up on the shaft, a guide roller for supporting the photosensitive element pulled out from the stock roller, a take-up roller rotatably supporting therein a take-up shaft for winding up a fatigued portion of the photosensitive element and formed with a slit for passing the photosensitive element to be wound up on the take-up shaft. and a frame for supporting the rollers rotatably. The guide roller is driven by a drive roller of the copier in rolling contact therewith, whereby the operative portion of the photosensitive element extending between the stock roller and the take-up roller is travelled back and forth for a copying operation.

The apparatus according to this invention for operating the photosensitive cassette comprises coupling means engageable with the stock shaft and the take-up shaft respectively and engageable with the stock roller and the take-up roller individually selectively and to thereby couple each of the rollers with the shaft housed therein for conjoint rotation, tension means engageable with and disengageable from the stock roller and the take-up roller to bias the two rollers in directions opposite to each other when in engagement therewith and to thereby tension the photosensitive element extending between the rollers, drive means engageable with and disengageable from the coupling means that is engageable with the take-up shaft to selectively engage with the take-up roller, the drive means being operable to drive the take-up shaft and the take-up roller in se quence when in engagement with the coupling means and to pull out the same from the stock roller, and operation means for controlling the operation of the tension means and the coupling means to successively effect the release of the photosensitive element from the tension, winding-up operation by the take-up shaft, operation by the take-up roller to pull out the photosensitive element and operation to tension the photosensitive element.

The tension means gives a suitable tension to the operative portion of the photosensitive element all the time to keep the element planar at the exposure station and to assure intimate contact of the element with copy paper.

The drive means and the operation means operate very accurately in an orderly manner under the control of electrical control means incorporated in the copier and renders the cassette of photosensitive element operable full-automatically.

Other objects and features of the present invention will become more apparent from the detailed description to follow.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a view in section showing the construction of principal part of an electrophotographic copier of the image transfer type, particularly of the electrostatic latent image transfer type;

FIG. 2 is a view in section showing an example of the cassette of photosensitive element;

FIG. 3 is a plan view partly in section showing the photosensitive element cassette;

FIG. 4 is a perspective view of an embodiment of the present invention which illustrates the details of a coupling portion between the rollers in the cassette of photosensitive element and operation means therefor;

FIG. is a perspective view showing a cassette loading station in the embodiment of this invention;

FIG. 6 is a perspective view showing the details of the operation means;

FIG. 7 is a side elevation in section showing the details of tension means; and

FIGS. 8(A), (B), (C) and (D) are plan views partly in section illustrating the operation of the embodiment of this invention, FIG. 8(D) particularly showing a cylinder cam in development.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an embodiment of electrophotographic copier of the electrostatic latent image transfer type. A

document D is placed face down on a document glass I and is illuminated by an iodine lamp L supported on an exposure system 2. The reflected light from the surface of the document is led by planar reflecting mirrors M1, M2, M3 and M4, image-forming lens 3 and exposure slit 4 to a photosensitive element P to form thereon the image of the document in the form of an electrostatic latent image.

The exposure system 2 in the illustrated apparatus comprises first movable means including the iodine lamp L and planar reflecting mirror Ml, second movable means including planar reflecting mirrors M2 and M3, and stationary means including the image-forming lens 3, planar reflecting mirror M4 and exposure slit 4. As detailed in Publication of Japanese Patent application No. 6647/]964, the first movable means L and M1 travel at a velocity of v from the solid line position to the broken line position in the drawing, while the second movable means M2 and M3 travel at a velocity of v/2 from the solid line position to the broken line position in the drawing, with the light path from the document surface to the image-forming lens 3 maintained at a constant length, so that the image of the original is formed on the photosensitive element P which travels at the same velocity v as the first movable means L and MI in synchronism therewith.

The photosensitive element P extends from a stock roller 5 to be described later to a takeup roller 6 by way of a guide roller 7 and is travelled at the velocity v by the guide roller 7 which is driven by a drive roller Disposed along the path of travel of the photosensitive element P are a cleaner 9, charger 10 the exposure slit 4, an eraser l1 and a transfer roller 12 for the cleaning, charging and exposure of the photosensitive element and the transfer of electrostatic latent image during the forward travel of the element P as already known. During the backward travel of the element P, the eraser ll eliminates residual charges.

Copy paper 13 in the form of a roll for bearing the latent image to be transferred thereto is accommodated in the machine. The leader portion of the paper pulled out from the roll is cut to a specified size by a cutter I4, and the cut-off sheet is brought into intimate contact with the latent image bearing surface of the photosensitive element P for the transfer of electrostatic latent image. The copy paper 13 is then separated from the photosensitive element F and supplied with a toner by a developing unit 15, whereby the latent image is visualized. The paper is thereafter transported on a belt 16 while the image is being fixed by a fixing unit 17 and is finally sent out onto a copy tray I8.

The cycle of copying operation described is typically of the mode of operation performed by one embodiment of electrophotographic copier of the electrostatic latent image transfer type. With an electrophotographic copier of the power image transfer type, a powdered toner is applied onto the photosensitive element P by a developing unit (not shown) immediately before the image is transferred, so as to visualize the electrostatic latent image. After the image transfer, fixing alone is conducted. with the developing step eliminated.

Since the construction and the copying operation of these electrophotographic copier of the image transfer type are already known, a detailed description will not be given. However, the present invention is not limited only to application for the copier of FIG. 1 but is adapted for electrophotographic copiers of both the latent image transfer type and the power image transfer type.

As exemplarily shown in FIGS. 2 and 3, a photosensitive element cassette C comprises a frame 20, and the stock roller 5, take-up roller 6 and guide roller 7 which are rotatably supported by the frame 20. The stock roller 5 has in its interior space a shaft 21 which is supported rotatably with respect to the roller 5. One end of the photosensitive element P in the form of a sheet is fixed to the shaft 21 and the fresh photosensitive portion is accommodated in the roller 5. The other end of the photosensitive element P is pulled out a required length from the roller 5 through a slit 5a therein. and part of the pulled out portion is wound around the stock roller 5 several turns. The photosensitive portion is then passed along a guide face 20a of the frame 20 and over the guide roller 7 disposed at an end of the guide face 20a. The leader end is then inserted into the roller 6 through a slit 6a therein and secured to a takeup shaft 22 which is positioned within the interior space of the roller 6 and supported rotatably with respect to the roller 6. As will be described later, part of the photosensitive portion, when fatigued through repeated use for copying operation, is taken up on the shaft 22 and is thereby accommodated within the take-up roller During the forward travel of the photosensitive element P for the copying operation, the take-up roller 6 winds up the operative portion of the photosensitive portion driven by the guide roller 7 and, during the backward travel of the photosensitive element, the wound-up portion of the photosensitive element P is unwound.

The apparatus of this invention includes operation means for winding up the repeatedly used and fatigued portion of the photosensitive element into the take-up roller 6 and for pulling out a required length of unused fresh photosensitive portion from the stock roller 5, means for imparting proper tension to the operative photosensitive portion to keep the same planar at the exposure station and means for effecting intimate contact of the photosensitive element with the copy paper at the transfer station.

The operation means will now be described.

As seen in FIGS. 3 and 4, the stock roller 5 and takeup roller 6 supported by the frame 20 of the cassette C have inner holes for rotatably supporting the shafts 21 and 22. The inner holes are splined as at 5b and 6b,

each at its one end. Projections exposed from the frame for supporting the shafts are provided with coupling pins Sc and 60 respectively. The shafts 21 and 22 in the rollers 5 and 6 are formed at their ends with splined holes 21a and 22a having a smaller diameter than the splined holes 5b and 6b.

The cassette loading station 23 of the copier is provided, as seen in FIG. 5, with cassette guides 26 and 27 fixed at their opposite ends to the opposing side plates 24 and to support the cassette frame 20 thereon. The loading station 23 is further provided with the drive roller 8 for travelling the photosensitive element P in timed relation to the movement of the first and sec ond movable means of the exposure system 2, the drive roller being adapted to be driven by unillustrated means. The drive roller 8 is in the form of a stepped roller comprising rubber rollers 29 for rotating the guide roller 7 by contact with the peripheral surface of its opposite ends and a shaft 28 for fixedly carrying the roller 29, the construction being such that the drive roller 8, out of contact with the surface of the photosensitive element P, drives the element P through the guide roller 7.

The side plate 25 rotatably supports tubular shafts 30 and 31 rotatably supporting roller coupling rods 32 and 33 in their inner holes respectively. The tubular shafts 30 and 31 are fixedly provided at their ends with discs 34 and 35, respectively. When the cassette C is loaded in place, pins 340 and 350 on the discs 34 and 35 engage with coupling pins 50 and 60 on the stock roller 5 and take-up roller 6 respectively, rendering the tubular shafts 30 and 31 rotatable with the stock roller 5 and take-up roller 6 respectively. The roller coupling rods 32 and 33 are stepped at their ends to provide splined portions 320, 33a and splined portions 32b, 33b, the former splined portions being greater than the latter in diameter. The splined portions 32a and 32b are engageable in splined holes 5b and 21a of the stock roller 5 and shaft 21 respectively, and the splined portions 330 and 33b are engageable in the splined holes 6b and 22a of the take-up roller 6 and shaft 22. The engagement of the splined portions 32a and 32b in the splined holes 5b and 21a respectively couples the stock roller 5 to the shaft 21, whereas the disenagment of the splined portion 320 from the splined hole 5b frees the roller from the shaft. Likewise, the engagement of the splined portions 33a and 33b in the splined holes 6b and 22a respectively couples the take-up roller 6 and its shaft 22 together, while the disengagement of the splined portion 33b from the splined hole 6b releases the roller 8 from the shaft 22.

As illustrated in FIG. 6, the tubular shafts 30 and 31 extend rearward through the side plate 25 to fixedly carry tension delivering gears 36 and 37 respectively. The coupling rods 32 and 33 extend through the tubular shafts 30 and 31 and project therefrom further rearward.

The delivering gears 36 and 37 are meshable with tension gears and 41 rotatably supported on a shaft 38 extending between the side plate 25 and a side plate 38 behind the plate 25. As seen in FIG. 7, the gears 40 and 41 are connected together by a spiral tension spring 42 interposed therebetween and having one end connected to the gear 40 and the other end secured to the gear 41. The tension spring 42, suitably tensioned, exerts a force on the gears 36 and 37 to urge the gears in opposite directions when the gears 36 and 37 come into meshing engagement with the tension gears 40 and 41 respectively, with the result that through the coupling pins 34a and 35a on the disc 34 and 35, the spring urges the stock roller 5 and the take-up roller 6 in such directions as to tension the photosensitive element P.

To control the biasing force of the tension spring 42 connecting the tension gears 40 and 41 together. there is provided means including a shaft 43 projecting from the front of the machine body and provided with a knob 44 (see FIG. 5) at its end. The other end of the shaft 43 is rotatably supported by the side plate 38. A stationary gear 45 meshable with the tension gear 41 is fixed to the side plate 38. In the illustrated embodi ment, the stationary gear 45 rotatably supports the rear end of the shaft 43. Alternatively, the stationary gear 45 may be replaced by an engaging member such as a pin that is engageable with a tooth of the tension gear 41.

The shaft 43 fixedly carries a gear 46 meshable with the other tension gear 40. When the tension gears 40 and 41 are shifted leftward in H6. 7 against the action of a spring 47 by means to be described later, one of the gears 40 and 41 comes into engagement with the stationary gear 45, with the other gear meshing with the gear 46 on the shaft 43. If the shaft 43 is then rotated by the knob 44, the gear 40 rotates, with the other gear 41 held stationary to tension the spring 42. Indicated at 48 is a coiled spring for preventing the reverse rotation of the shaft 43 during the tensioning.

A cylinder cam 50 on a shaft 49 extending between the side plates 25 and 38 as shown in FIG. 6 governs the shifting of the tension gears 40 and 41 on the shaft 39 for engagement with the tension delivering gears 36 and 37 or with the spring tensioning gears 45 and 46 and also governs the coupling of the stock roller 5 with its shaft 21 and coupling of the take-up roller 6 with its shaft 22 (i.e., coupling and uncoupling between the relevant splined portions) by means of the coupling rods 32 and 33.

The cylinder cam 50 is formed in its circumferential surface with two cam grooves 50a and 50b. An actuating plate 51 having a driven portion 51a engaged in the cam groove 50a is pivotally supported by a pin 53 on a bracket 52 secured to the side plate 25. The actuating plate 51 has a forked upper end 51b engaged in a groove 400 formed in the assembly of the tension gears 40 and 41. An inverted L-shaped actuating plate 56 has at its lower end a driven protion 56a engaged in the other cam groove 50b, the actuating plate 56 being supported by a pin 55 on a bracket 54 secured to the side plate 38. The upper portion of the actuating plate 56 has one end 56b held in engagement with the end of the coupling rod 32 by a washer 32c and the other end 56c held in engagement with the end of the coupling rod 33 by a washer 33c. As the cylinder cam 50 rotates, the actuating plate 51 causes the tension gears 40 and 41 to move slidingly on the shaft 39, and the actuating plate 56 causes the coupling rods 32 and 33 to slide within the tubular shafts 30 and 31 axially thereof.

The cam grooves 50a and 50b of the cylinder cam 50 are so shaped as shown in FIG. 8(D) in development. The operation of the cam will be described later.

A rotary solenoid 57 governs the rotation of the cylinder cam 50. The rotary solenoid 57 rotates through l20 (one-third of one revolution) at a time, and the torque is delivered to the cylinder cam 50 through claw clutches 58 and 59. By suitable electrical means such as programming control circuit (not shown), the rotary solenoid 57 is adapted to be actuated into operation when the photosensitive element cassette C is loaded and when a fatigued photosensitive portion is wound up and a fresh portion is pulled out.

The rod 33 for coupling the take-up roller 6 with its shaft 22 is provided at its rear end with a driven gear 60 which is meshable with drive gears 62 and 63 on a drive shaft 61 rotatably supported by and extending between the side plates 25 and 38. Indicated at 64 is a motor for driving the shaft 6]. Through a sprocket transmission 65 and an electromagnetic clutch 66, the motor drives gears 67 and 68. The gear 67 in turn rotates the shaft 61 through a sprocket transmission 69.

The other gear 68 to be driven by way of the electromagnetic clutch 66 has a cam 70 integral therewith for defining the length of the operative portion of photosensitive element P. The cam 70 is in engagement with an actuator for a microswitch 71, such that the rotation of the cam 70 controls the operation of the electromagnetic clutch 66 through the microswitch 71 and thereby controls the winding of the photosensitive element P onto the take-up shaft 22 and the length of the photosensitive element P to be paid out from the stock roller 5.

During a copying operation, the driven portion 51a of the actuating plate 51 and the driven portion 56a of the inverted L-shaped actuating plate 56 engage in the cam grooves 500 and 50b of the cylinder cam 50 at a position C indicated in the development of FIG. 8(D). Accordingly, the tension gears 40 and 41 whose position is determined by the cam groove 50a are located at the position shown in FIG. 8(C) and mesh with the tension delivering gears 36 and 37 respectively, permitting the tension spring 42 to elastically act on the stock roller and the take-up roller 6 through the discs 34 and 35. Likewise, the roller coupling rods 32 and 33 whose position is governed by the other cam groove 50b are located at the position shown in FIG. 8(C), coupling the stock roller 5 with its shaft 21 and the take-up roller 6 with its shaft 22 by the splined portions 32a, 32b and 33a, 33b respectively for conjoint rotation. Consequently, the elastic force of the tension spring 42 acts as a tension on the photosensitive element P to keep the element P planar and to fit the same intimately with the copy paper during the reciprocation of the photosensitive element for the copying operation. During the copying cycle, the operative portion of the photosensitive element P is wound up around the take-up roller 6 when travelling forward and is wound up around the stock roller 5 when travelling backward. The reciprocal travel of the photosensitive element P is effected by the drive roller 8 which rotates the guide roller 7 in the forward and backward directions.

When the operative portion of the photosensitive element has been fatigued due to repeated use, the exposure system 2 will be stopped at the solid line position in FIG. l(with the photosensitive portion in use wound around the stock roller 5 as shown in FIG. 2). A button for taking up and paying out on an unillustrated operation panel is then depressed, whereby an unillustrated electric control circuit in the machine is operated to energize the solenoid 57, which in turn rotates the cylinder cam 50 through 120 from position C to position A. This causes the cam groove 50a to move the actuating plate 51 pivotally about the pin 53, bringing the tension gears 40 and 41 from the position of FIG. 8(C) to the position of FIG. 8(A) out of meshing engagement with the tension delivering gears 36 and 37 to free the photosensitive element P from the tension. At the same time, the gear 40 meshes with the gear 46 for controlling the tension and the gear 4] with the stationary gear 45. Thus in this state, the elastic force of the tension spring can be adjusted as already described.

The foregoing rotation of the cylinder cam 50 per mits the cam 50b to move the inverted L-shaped actuating plate 56 pivotally about its pin 55 to move the coupling rods 32 and 33 in the directions of the arrows in the drawing, When thus moved, the coupling rod 32 has its splined portions 32a and 32b simply pushed into the splined holes 5b and 21a, keeping the stock roller 5 coupled with the its shaft 21, whereas the movement of the coupling rod 33 brings the driven gear 60 into meshing engagement with the drive gear 62 and disengages the splined portion 330 from the splined hole 6b of the take-up roller 6, rendering the roller 6 free to rotate with respect to the take up shaft 22. Thus, the roller 6 is uncoupled from the shaft 22. Further since the splined portion 33b is simply shifted within the hole 22a, the splined portion 33b remains in engagement with the splined hole 220.

In this state, the programming circuit in the electric control] circuit or some other operation means operates to energize the electromagnetic clutch 66, causing the motor 64 to drive the shaft 61, which in turn rotates the coupling rod 33 through the gears 62 and 60 to wind up the fatigued portion of the photosensitive element P on the take-up shaft 22. Since the tension gear 40 is out of engagement with the gear 36, the stock roller 5 permits the photosensitive element P to be unwound from its outer periphery as the winding operation proceeds. The take-up roller 6, out of rotation, allows the photosensitive element to be taken into the roller through the slit 60.

Upon completion of the winding operation, the electromagnetic clutch 66 is temporarily deenergized to interrupt the transmission of the torque of the motor 64 to stop the shaft 61. At the same time, a signal is sent to the rotary solenoid 57, causing the solenoid 57 to rotate further l20C to bring the cylinder cam 50 from position A to position B in FIG. 8(D). This does not move the actuating plate 51, leaving the tension gears 40 and 41 still in meshing engagement with the gear 46 and the stationary gear 45 respectively, whereas the cam groove 50b moves the inverted L-shaped actuating plate 56, which in turn shifts the coupling rod 32 toward the direction of arrow as seen in FIG. 8(B). The splined portion 32a therefore disengages from the splined hole 5!) of the stock roller 5 to uncouple the stock roller 5 from the shaft 21. (In this state, the splined portions 3212 which has been simply shifted within the splined hole 210 is still in engagement therewith.) Through this movement, the other coupling rod 33 moves in the direction opposite to that of the foregoing movement to engages its splined portion 330 into the splined hole 6b of the take-up roller 6 and to thereby couple the take-up roller 6 with the shaft 22 for conjoint rotation. At the same time the gear 60 is brought into meshing engagement with the gear 63 on the shaft 61.

The programming circuit or the like again energizes the electromagnetic clutch 66 to cause the motor 64 to rotate the shaft 61, which drives the coupling rod 33 through the gears 63 and 60, whereby the take-up roller 6 and its shaft 22 are driven together to wind up the photosensitive element P around the outer peripheral surface of the roller 6. This winding operation rotates the shaft 21, while the stock roller remains stationary since it is uncoupled from the shaft 21, permitting a fresh portion of the photosensitive element P to be pulled out through the slit 5a.

When a predetermined length of the photosensitive element has been pulled out, the defining cam 70 which has been rotating along with the clutch 66 actuates the microswitch 71 and deenergizes the electromagnetic clutch 66 to interrupt the transmission of the torque of the motor 64. The shaft 61 stops, whereupon the winding of the element around the take-up roller 6 is completed.

Subsequently, the programming circuit or the like operates to rotate the rotary solenoid further 120 and brings the cylinder cam 50 from position B to position C in FIG. 8(D), forcing the cam grooves 50a and 50b to move the actuating plates 51 and 56. This shifts the tension gears 40 and 41 and coupling rods 32 and 33 from the position of FIG. 8(8) to the position of FIG. 8(C), bringing the gears 40 and 41 into meshing engagement with the gears 36 and 37 respectively and disengaging the same from the gears 46 and 45. At the same time, the gear 60 is released from the gear 63, and the splined portion 32a engages in the splined hole 5b, rendering the stock roller 5 rotatable with the shaft 21 by coupling.

As a result, the tension spring 42 acts on the coupling rods 32 and 33 to bias them toward directions opposite to each other and thereby tensions the photosensitive element P. The drive roller 8 now drives the guide roller 7, which unwinds the photosensitive element P from the outer periphery of the take-up roller 6 and rewinds the same around the stock roller 5. The parts are thus set in position, ready for copying operation.

The photosensitive element extending between the stock roller 5 and the take-up roller 6 is repeatedly used thousands of times and, when the photosensitive portion gets deteriorated, the old portion is wound up into the take-up roller 6 and a fresh portion is pulled out from the stock roller 5 for use.

When the fresh photosensitive portion in the stock roller 5 has been used up, the old cassette is unloaded from the copier and replaced with a new one. At this time the respective parts are located as seen in FIG. 8(C), so that upon loading the new cassette, the machine is made ready for a copying operation. If the operative portion of photosensitive element P in the new cassette is not long enough as specified, the forcing taking-up and pulling-out operation is conducted to pay out a required length of the element.

Since the electric circuits for automatically controlling the operations of the respective mechanisms by push button operation and programming control are not principally contemplated by this invention, description will not be given therefor. The electric circuits can be so designed as to effect the foregoing operations in sequence.

What is claimed is:

1. An apparatus for operating an image transfer element cassette in an electrophotographie copier of the image transfer type comprising:

a loading station for the image transfer element cassette,

coupling means engageable with a stock shaft and a take-up shaft when the cassette is loaded in place, the stock shaft and the take-up shaft being rotatably supported in a stock roller and a take-up roller rotatably supported on a frame of the cassette, the coupling means being operable to engage with the stock roller and the take-up roller individually selectively and to thereby couple each of the rollers with the shaft housed therein for conjoint rotation,

tension means engageable with and disengageable from the stock roller and the take-up roller to bias the two rollers in directions opposite to each other when in engagement therewith and to thereby tension the photosensitive element extending between the rollers,

drive means engageable with and disengageable from the coupling means engageable with the take-up shaft to selectively engage with the take-up roller, the drive means being operable to drive the take-up shaft and the take-up roller in sequence when in engagement with the coupling means and to thereby wind up the photosensitive element and pull out the same from the stock roller, and

means for moving the tension means into engagement with and out of engagement from the stock roller and the take-up roller and means for moving the coupling means into engagement with the stock roller and the take-up roller selectively.

2. The apparatus as set forth in claim I wherein the coupling means comprises two coupling rods stepped to provide splined portions engageable in splined holes formed in the ends of the stock shaft and the take-up shaft respectively and to provide splined portions of a greater diameter engageable in splined holes of a greater diameter formed in the ends of the stock roller and the take-up roller respectively, the coupling rods being shiftable in axial directions opposite to each other under the control of the operation means to selectively engage the greater diameter splined portions in the greater diameter splined holes, the coupling rods being rotatable by the drive means when required.

3. The apparatus as set forth in claim 1 wherein the tension means comprises an assembly of two gears biased to rotate in directions opposite to each other and two tubular shafts in engagement with the stock roller and the take-up roller and having gears meshable with the gears respectively when the assembly is shifted, and the stock roller and the take-up roller are biased in di rections opposite to each other when the gears mesh with each other respectively.

4. The apparatus as set forth in claim 1 wherein the tension means includes means for adjusting the biasing force acting between the two gears.

5. The apparatus as set forth in claim I wherein the drive means includes a cam for defining the length of the photosensitive element to be wound up and the length of the same to be pulled out during the image transfer element winding-up and pullingout operations to stop the drive means upon completion of the winding-up and pulling-up operations.

6. The apparatus as set forth in Claim 1 wherein the means for moving the tension and coupling means comprises a cylinder cam formed with two cam grooves in its peripheral surface and rotatable through for each cycle of the winding-up, pulling-out and tensioning operations, said means for moving the tension means into engagement with and out of disengagement from the stock roller and the take-up roller is under the control of the first cam groove, and the means for moving the coupling means into engagement with the stock roller and the take-up roller is selectively under the control of the second cam groove.

7. An image transfer web cassette for an electrostatic copying machine comprising a body member, a pair of transversely spaced parallel take-up and feed shafts independently, rotatably supported by said body memher, a pair of transversely spaced take-up and feed reels coaxial with respective shafts and supported for independent rotation relative to each other and said shafts, each of said reels having a longitudinal opening providing access to the respective shafts, a separable drive coupling connected to each of said reels and shafts, and

an image transfer web extending between said reels and projecting through said access openings into engagement with said shafts.

8. The cassette of claim 7 wherein said coupling means comprise telescoping splined shaft sections projecting from the take-up shaft and reel and the feed shaft and reel.

9. The cassette of claim 7 wherein each of said reels comprises a hollow drum having a longitudinal slot defining a respective access opening.

10. The cassette of claim 7, including a guide roller transversely spaced from and parallel to said reels. said web extending from one reel along a predetermined path about said guide roller and to the other reel. 

1. An apparatus for operating an image transfer element cassette in an electrophotographic copier of the image transfer type comprising: a loading station for the image transfer element cassette, coupling means engageable with a stock shaft and a take-up shaft when the cassette is loaded in place, the stock shaft and the take-up shaft being rotatably supported in a stock roller and a take-up roller rotatably supported on a frame of the cassette, the coupling means being operable to engage with the stock roller and the take-up roller individually selectively and to thereby couple each of the rollers with the shaft housed therein for conjoint rotation, tension means engageable with and disengageable from the stock roller and the take-up roller to bias the two rollers in directions opposite to each other when in engagement therewith and to thereby tension the photosensitive element extending between the rollers, drive means engageable with and disengageable from the coupling means engageable with the take-up shaft to selectively engage with the take-up roller, the drive means being operable to drive the take-up shaft and the take-up roller in sequence when in engagement with the coupling means and to thereby wind up the photosensitive element and pull out the same from the stock roller, and means for moving the tension means into engagement with and out of engagement from the stock roller and the take-up roller and means for moving the coupling means into engagement with the stock roller and the take-up roller selectively.
 2. The apparatus as set forth in claim 1 wherein the coupling means comprises two coupling rods stepped to provide splined portions engageable in splined holes formed in the ends of the stock shaft and the take-up shaft respectively and to provide splined portions of a greater diameter engageable in splined holes of a greater diameter formed in the ends of the stock roller and the take-up roller respectively, the coupling rods being shiftable in axial directions opposite to each other under the control of the operation means to selectively engage the greater diameter splined portions in the greater diameter splined holes, the coupling rods being rotatable by the drive means when required.
 3. The apparatus as set forth in claim 1 wherein the tension means comprises an assembly of two gears biased to rotate in directions opposite to each other and two tubular shafts in engagement with the stock roller and the take-up roller and having gears meshable with the gears respectively when the assembly is shifted, and the stock roller and the take-up roller are biased in directions opposite to each other when the gears mesh with each other respectively.
 4. The apparatus as set forth in claim 1 wherein the tension means includes means for adjusting the biasing force acting between the two gears.
 5. The apparatus as set forth in claim 1 wherein the drive means includes a cam for defining the length of the photosensitive element to be wound up and the length of the same to be pulled out during the image transfer element winding-up and pulling-out operations to stop the drive means upon completion of the winding-up aNd pulling-up operations.
 6. The apparatus as set forth in Claim 1 wherein the means for moving the tension and coupling means comprises a cylinder cam formed with two cam grooves in its peripheral surface and rotatable through 120* for each cycle of the winding-up, pulling-out and tensioning operations, said means for moving the tension means into engagement with and out of disengagement from the stock roller and the take-up roller is under the control of the first cam groove, and the means for moving the coupling means into engagement with the stock roller and the take-up roller is selectively under the control of the second cam groove.
 7. An image transfer web cassette for an electrostatic copying machine comprising a body member, a pair of transversely spaced parallel take-up and feed shafts independently, rotatably supported by said body member, a pair of transversely spaced take-up and feed reels coaxial with respective shafts and supported for independent rotation relative to each other and said shafts, each of said reels having a longitudinal opening providing access to the respective shafts, a separable drive coupling connected to each of said reels and shafts, and an image transfer web extending between said reels and projecting through said access openings into engagement with said shafts.
 8. The cassette of claim 7 wherein said coupling means comprise telescoping splined shaft sections projecting from the take-up shaft and reel and the feed shaft and reel.
 9. The cassette of claim 7 wherein each of said reels comprises a hollow drum having a longitudinal slot defining a respective access opening.
 10. The cassette of claim 7, including a guide roller transversely spaced from and parallel to said reels, said web extending from one reel along a predetermined path about said guide roller and to the other reel. 